I realize the original question was ASA.
For NFHS rules (1-4-3), there is nothing said about "first baseman" gloves. There are ONLY size restrictions - heel to tip, 14 inches max, etc.
Are first baseman gloves typically larger than this?
Has anyone ever made the effort to measure a glove during a game?
A team complained to me last year about a SS using a first baseman glove. Not having a tape measure I said it didn't matter what style of glove was used. Hope I was right.