Grenadier Reg. 10 vs. Bav. I.R. 10

[dksck]

I'm not certain that this is the right place to put this question, so please forgive me if it needs to be relocated.  

I'm having trouble distinguishing between items connected to Grenadier Regiment Nr. 10 and Bavarian Infantry Regiment Nr. 10.  I have a piece of equipment marked "10.R.M.G.24"  According to one book by Gortz, the mark "10.R.M.G.24" indicates Grenadier Regiment Nr. 10 but according to the longer book if it was Gren. 10 it would be 10.G.R..M.G.24.  So what unit is this item from?  But now what about photos, documents, etc. that are marked "Infanterie Regiment 10" or some variation of that -- no "G" or "Gren"?  For example, what about photos of guys wearing helmet covers with just a number "10"?  Is that Gren. 10 or B.I.R. 10?  Or something else?  I finally figured out many of the photos with "10" shoulder boards are from Train Bataillon Nr. 10 because of the geographical location of the photo or other context.  But what about a Wehrpass or other document that identifies the unit as "Infanterie Regiment Nr. 10" but it's not a Bavarian document?  Was Grenadier Regiment Nr. 10 referred to as IR 10 casually and/or in print at times?  Or does "Infanterie Regiment Nr. 10" or variant in print or written, indicate it is really Bavarian I.R. 10?   Your thoughts and help are greatly appreciated.

Edited February 29, 2020 by dksck