I would say a qualified yes. Religion and theology are not distinct from philosophy, and traditionally have been a source of philosophical thought. To a certain extent, it depends on metaphilosophical attitudes because this appears to be a question within the confines of metaphilosophy itself.
For the record, the only related meta post seems to be Theology tag equivalence.
Now, metaphilosophy is just the use of philosophical methods to examine philosophical methods. Besides, the notion that the thinking of Thomas Aquinas is NOT philosophical would be very hard to defend. The historical trajectory from polytheistic myth to philosophy to theology to natural theology to science is an undeniable fact of the historicity of the lineage of theory in the eyes of the philosophy of language. However, there are strategies to focus on the philosophical aspects of these thoughts which need to be observed. My rule is simple requiring a consistency in terminology, methods, and goals. To the extent the question complies with the criterion, the question complies with philosophy:
The Weak Philosophical Razor of Demarcation I offer for handling the demarcation of religion from philosophy is this: Is the question phrased in the terminology of philosophy using the methods of philosophy for the aims of philosophy as opposed to being in the terminology of the religion using the methods of the religion for the aims of the religion?
This of course can be generalized to:
The Strong Philosophical Razor of Demarcation I offer for handling any demarcation: Is the question phrased in the terminology of philosophy using the methods of philosophy for the aims of philosophy as opposed to being in the terminology of some other discipline using the methods of some other discipline for the aims of some other discipline?
To the extent (this is not a question of binary logic) that the answer to the razor is yes, the answer to your question is yes. Hence, the qualified yes.
In a text, for instance, it's possible to infer the authors tone and attitudes. Using a discussion about "religious structure" to convert disqualifies, but asking questions about the identity, history, logic and fallacy, or meaning (not all at once please!) of the "religious structure" would very much be very appropriate. If one can apply the philosophy of language, the philosophy of mind, the philosophy of religion, or some other philosophy to questions about arguments in religion, than it's clearly a philosophical topic. If one applies the reasoning to proselytize or defend the moral absolutism of the argument, one is preaching. I've seen both on the site, so if you stick to the former, you'll have an easier time defending.
Now, the natural follow-up to this question is what are the strategies to keep this out of the theology category or avoid being off-topic, and what are those that make it a good philosophical question. This is a matter of some concern to this site since over the last ten years, the site seems to have changed from how it was used originally to how it is currently being used. I can't say that I can even adequately characterize the transformation because of my relative newness to the site. What I can say is that to address the details where the devil hides, it might help to start with the following two posts after reading the community FAQ:
FAQ for Philosophy.SE
Friends, Are We Not Philosophers: Is This Place a Bazaar or a Cathedral?
Friends, how could a question about an idea with its own article in the Stanford Encyclopedia of Philosophy be closed as off-topic?
There are some inherent tensions here as to what this site is and how it should be used. A good discussion about the tensions can be found at https://stackoverflow.blog/2012/03/22/respect-the-community-your-own-and-others/.
My suggestion would be to jump in and take a shot at the question, and see what happens after you review. Definitely search for your question first and see what is in the knowledge base, and then do your best to formulate a question according to some of the ideas in the links above. After that, if you have problems or questions, use the comments section below to seek clarification. If that doesn't help, you can post a follow-up question here on Meta for details.
Be prepared for strong opinions on the nuances between religion, the philosophy of religion, the use of philosophy in religion, and religious philosophy which might rear their heads. You may be besieged philosophical attacks in the comments, with votes for closure often without critical feedback on why, or occasionally abusive ad hominem. Don't take it personal, and know there are mechanisms for handling such events.