Jon, tell him to write his auto-bibliography as his next book. I'll read it as I read his fantasy one full of 'doubts'.
And, please, don't torture us longer - just say it.
Costumes are anywhere from Stewarts to Gorgian (especially coffs, collars can be little late as well), guns look more like, at least, Restauration and the guy on left definitely has English/British hat so film must be Great Britain/early US based. Not mentioning that they both look awefully familiar. So, what was it???