I don't have anything that size, as it appears the ones we have are newer as well. The ones we have are the quick-release type that allow arm removal from the mounting base.
You may be able to modify your older style arms to fit the newer type, or you could make a bracket from aluminum flat bar and some angle clips.
I would think that you could find the style you on ebay as well. It may take some vigilance but older awning pieces and parts do show up in listings.
You can also check with Colaw's RV Salvage first.