I bought my k75s a few months ago and the previous owner informed me, to my dismay, that this particular model of case could not be locked. how sad.
I found out last night that he was wrong! :yow
I looked at my cases and, of course, they don't match. One uses #58 and one uses #52. I found the #58 key at
MAX BMW.... actually, I found it on ebay for $25 and was just about to bite the bullet when I realized I could get it from MAX for half the price!
Still looking for the #52 key. Any suggestions? Part number appears to be 51250418962 NLA SDL-BAG KEY 052