looks identical to the bolts that came with a toilet wax ring I just installed. You could probably find these bolts at a hardware plumbing section

http://forums.pelicanparts.com/uploa...1596219699.jpg

Trailex also uses them to hold most of their aluminum trailers together. Drill a hole in your anvil and hammer a hex bolt head flat then file/grind to fit.
Also
https://www.rockler.com/t-slot-bolts-pack-of-five-1-4-20-thread?country=US&sid=V91040&promo=shopping&utm_so urce=google&utm_medium=cpc&utm_term=&utm_content=p la&utm_campaign=PL&tid=pla&gclid=Cj0KCQjwgo_5BRDuA RIsADDEntSo-BjBVN3dzt6yPHelx48C3sl6QhHk6XwnOfodQRPO-QIYilrM05EaAks_EALw_wcB

There are absolutely weld marks where the original weld studs were positioned.

However, the only stainless acorn nuts were 1/4-20 at Lowes, so brass toilet bolts for the win.


http://forums.pelicanparts.com/uploa...1599066886.jpg

http://forums.pelicanparts.com/uploa...1599066909.jpg

http://forums.pelicanparts.com/uploa...1599066940.jpg

New, I hope

I love me some home depot engineering.

Dad's old '64 Travelall had mirrors a lot like that on it.
Had three gas tanks @60 gals total, split rims, it was a 1200 series.
They don't make them like that any more.

Beat me to it, by a month - toilet bolts is what I thought as well. http://forums.pelicanparts.com/uploa...1599094527.jpg

Those non-wax rings are great. Reusable and a more secure seal. The void in the base of the toilet makes a good hidey hole. These rings make it simpler to use it.

T bolt or Trim bolt.