SL400 versus SL400c

[clasys]

Recently an SL400 crossed my worktable and long story short, Lenovo sent [out of warranty] a replacement top bezel with SL400c on it.

The owner has issues as to whether this is a "downgrade" of the machine that perhaps he has to defend as in "Yes, it says it's a c but it's actually the regular sl400" should he sell it, etc.

I can't find any clues in the manuals, so I am wondering if this is merely some build-to-order distinguish without a difference thing, or is there some actual clearly statable differences between SL400 and SL400c [enquiring repairmen want to know!].

Thanks for any pointers to the exact differences; seen too much same-exact docs.

cjl [many a ThinkPad has crossed these hands. You can tell by the large piles of screws of so many varieties not to mention a lot of worn-out cheap mini-screwdrivers]