I recently bought a used UMP45 from a player, but sadly he had no information about it's make and model. I'm trying to figure out if it's G&G, DE, ARES, or if it's another manufacturer.
Ex-friend of mine said it's probably ARES based on the looks and the insides, but I don't trust him anymore, so any help would be appreciated. I will upload some photos tomorrow if needed, but for now I can say the following:

HK engravings on both sides (chamber cover has HK .45 Auto on it, left side has HK UMP, licenced trademark, etc.)
Serial number: VE002264 (assuming it's unique and not just added for show)
Unthreaded outer barrel.

Question is basically to figure out if I need to buy specific midcaps for it, or the G&G "UMG" mags will work just fine, because currently those are the only ones in stock in my general (CEU) area.

Thanks for any and all help you may be able to provide.