I think the French and Belgian guns were posted as exemplars of how clear the post-er(s) would like the pics of the drilling's proofs to be.
All I can make out on the pics of the drilling is a "nitro" mark on the bottom of the RH shotgun barrel.
I'm dubious about what someone identified as a "flaming bomb" b/c that's both a US military mark (and therefore unlikely to be on a drilling looking like this one) and something that would set off alarm bells in ATF if one were to try importing (or bringing back) a gun bearing same. Might be a crown, which would be consonant with a pre-war German drilling.
