TH350 Dipstick replacement? & funny parts counter conversation

[Toro]

I need a new dipstick for my TH350 in my '72 Blazer. So, based on a quick search here, several other threads pointed out the part might still be available from GM. I called my local Chevy dealer parts dept., and after explaining what I was looking for, they told me "I'm not sure Chevrolet made the Blazer". Needless to say, I didn't find the part.

Has anyone replaced this before and know of a good part number/source? A quick search around the usual parts suppliers show a wide variety that all look completely different and all say they fit the TH350.

Thanks for the help,
Jon