For what it's worth, here's my take on the plate and weight pricing - I don't feel $50~ extra for a PVD brass plate upgrade is too out of the ordinary, considering there are several options being offered rather than just the one plate for every layout (as is with most TKLs or 65%, etc) I can understand that the cost may be justifiable and I have seen similar situations with other very successful GBs.
That said, at just like 7-10 bucks extra for the plate and weight respectively to just get an extra on top of your already included versions, that's a disproportionately attractive deal in my opinion. If the prices remain as is, there's no real reason to flat out replace your standard options, rather just get a set of extras for like $15 together with an extra PCB if you're worried about it being proprietary and not being readily available if something does happen to your other one.
PS: the weight is expensive either way you go about it however, but without knowing how the machining etc works I'd rather not comment/complain.