I learned a similar lesson with a little green 185j...we stopped in at a local thrift store on our way to visit a friend and found a gorgeous machine in a case, all intact. Well, trying to be responsible because I already have one in a cabinet we left it behind - that machine bugged us all day until we stopped in again on our way home and guess what - she was still there but the needleplate etc was missing :-( :-(
...still bugs me when I think about it!