Wow, that R-P is older than mine! I think mine is a 1936 model, serial number 15138. The one at HGR is 14075.
My R-P is a 16x80 with a much higher spindle speed than most R-P lathes of this era. It got a good workout this last week making a dump-truck driveshaft from heavy wall tubing.
I think the 'patina' is just faded and stained yellow paint on the carriage/apron and tailstock of that machine at HGR. Looks to be a great deal for occasional use or a collector. I love that taper attachment... mine doesn't have one...
When you zoom in on the pictures, that is rust. HGR's warehouse has a leaky roof. It wouldn't surprise me if it sat under one of the bad leaks for several years of saturated moisture either in their warehouse or an old shop where the lathe came from.
They also have a Axelson I would love to have, like I need another project. All the handwheels, levers on the carriage are broken off, typical of HGR handling.