like the pogs, early borons were made in the u.s., later runs, china.
like prostaffs, early borons were bumperless and later borons sported bumper/grommet systems.
earliest borons had individual grommets - VERY hard to find replacements
earlier borons had numeric serial numbers, later runs had alpha-numeric SNs
there were minor labelling variations between earlier and later versions.
earlier borons came with nicer leather covers (almost coach level of quality), later lesser and some with faux-suede vis-a-vis four stripe pogs.