The OCT-19 for RED on eBay isn't my mount.
I sell one using the Cinevate OCT-19 receiver and my intermediary unit. It has a cut out for the L shaped brackets that you find on some of the OCT-19 lenses.
Not all OCT-19 lenses will fit on this mount, or the RED camera. Some have a rear lens/bracket depth that would contact the RED adjustable collar and just won't work. You might be able to use them for close up work, but maybe not even that. I don't have a list of which lenses work and which don't because it seems that there are so many different types, made over so many years for different cameras. But if you email me a photo of the rear of your OCT-19 mounted lens, I can give you a good guess as to whether or not it would work on a RED.
The round and square front Lomo scope lenses all seem to work, at least the ones that I have seen.
The OCT-19 mount is really an excellent mount. It's the biggest one commonly used for cine work, bigger even than the Mitchell BNCR, and it is very strong. So if you don't mind swapping mounts on your RED, it works well. A lot of users spend the money and get their Lomos and Ekrans converted to PL, though.