I've been curious about it ever since I got my first one with the OM marking. It's a #718 that fits my 5" HD perfectly. That one also has the 'bar-oval' maker's mark, but the holster just doesn't look - or feel like a piece of pre-1925 gunleather. As I said earlier, every Heiser I have or have seen marked 'OM' has been a perfect fit for an N frame.
I also question some of the info on the VGL site. They don't even know what most of their holsters fit. I tried to buy a holster from the original owner of VGL years ago, but raised the price - not once, but
twice, so I pretty much told him what he could do with it.
Mark