Weight of Isle of Man crowns

Blackhawk

I have a few isle of man crowns from 1990-1994. They all look like proofs to me. Is there a way to tell the difference of the CuNi and silver issues by weight? The weight of the silver pieces are listed in Krause, but I can't find anything about the CuNi model?

RobP

I would assume they are the same weight as the silver ones at 28.28g as in the case with Royal Mint issues. Presentation packs usually give the statistical info, but I don't have any IOM packs.