Oh, my apologies. Yeah, I misunderstood what you are describing.
I was going to come back and ask if you're looking for replacement arms. The Roadmaster 1424-1 isn't obsolete as far as I know and replacement arms can be ordered. Here's the order form ...go HERE
But you must be asking something else other than wanting the arms but if you do, as you can see, the arm part numbers are C-000478 for the left/driver's side and C-000479 for the right/passenger side or 13 and 14 on the parts diagram. You can also call Roadmaster up here in the Pacific Northwest if you do need any baseplate part or have questions about the brackets. They used to have very good customer service but I haven't called them or dropped in to see them recently.
But if Bangorbob
can help you privately, that's great. I didn't catch that both of you are now in Pahrump as we lived there for about 6 years quite a few years ago. So we all may have been there at one time for all we know.