Unfortunately, you really can't find out much about them anymore unless you happen to run across a mama who keeps track of what her Mollytogs were made of. Amy, the mama who made them, appeared to use all different fabric combinations in her dipes.
As for how much they go for... I've gotten some used ones really cheap, I think the longer she has been gone from WAHMhood the more people have forgotten about or never knew about Mollytogs. They seem to have been universally loved though so you never can tell who you might get into a bidding war with them if you see them on eBay. So depends how much they are worth to you, kwim?