I'm not sure there are any "factory" HK45C LEM models, light or standard. Certainly my German-produced "factory" HK45C LEM was converted from standard V1 to LEM by HKI in Columbus GA after importation and before it went in the distribution channels. Perhaps the USA-produced pistols will be true-factory LEM.
Makes not a twit of difference, though. These are all HK parts so don't worry about what LEM version it might be. A pair of $5 springs gets you whatever version you want in about 15 minutes at your kitchen table: trigger rebound and hammer springs. Complete conversion to LEM is about $80 for the HK kit.
BTW, my HK45C was standard LEM -- AKA "Heavy" LEM -- and the dealer was glad to "get rid" of it because of the horrible 9+ pound trigger. I'd previously gone thru a two-step LEM conversion with my USP9C, first to standard then light LEM, so I knew I could fix the HK45C trigger easily with a couple of HK springs.
-- Chuck