WTF?
Nothing on a 4473 that would denote if the purchaser is LE, Mil or any other such thing.
The only thing I can think of is where the dealer section "B" of the 4473 20a "Identification" and 20b "Alternate Documentation" may show a LE or MIL identification.
But I know plenty of LE and MIL used their private ID to purchase under the Blue Label program.
Absolutely NO reason a manufacturer would need info from a 4473.

Sounds like the dealer lacked integrity on the BL program and Glock called them on it.