I just had a quick look at two Pluses (UK sourced) and both have the "Macintosh Plus 1MB" label. One of them is definitely Platinum and a very late model. I know the bloke who sold it although the company and sales records have long disappeared. My recollection is that it shipped with 1MB because I would remember if I had downgraded. Incidentally, the label actually says "Macintosh Plus 1Mb" (sic).

A study of back panel labels might be interesting, but without access to manufacturing records it will be meaningless. Apple branding of compact Macs in Europe, Australia and Japan was different from that in North America and there were an awful number of "specials".

In North America, Apple sold many different Performa models that were badged according to the seller/distribution channel and software bundle. Identifying every variation is futile because under the case it is just an LC or Classic or PowerMac.