Janette, I am a bit confused.
You asked about more info for the 1985 one ... which I think is the one that I commented on as being a PP77. So yes, it does have a PP number. And the fact that it was only made in 1985 means it was a limited edition.
The PP number was simply the factory numbering system for annual limited edition and general weights (i.e. those produced across many years) and was allocated sequentially starting at PP1. There were other limited editions which were produced as an "Annual Collection" item, "Christmas" items and "Special Edition" pieces and these did not have a PP number. For the (annual) limted editons, total numbers made in each year could be from 250 to 400. For the other limted editions, numbers made were very variable with as few as 50 or as many as 1,000 being allocated, but often actual production was less than the allocated number.
Again, info is from The Complete Guide to Perthshire Paperweights - well worth purchasing.