Received mine, but separated from my Sun Cat until mid September so unable to 100% verify fitment. Seems quite stout, maybe even heavier gauge stainless than OEM.
https://drmarine.com/product/gooseneck-slide-only/
Looks right, let us know if it works. I see reference to O'Day Spars on the Dwyer site, under Parts By Boat, but there are no products associated. My guess is that DR Marine is sourcing the parts from Dwyer. Bottom line, no machined fittings here, plenty of slop.
I see the Dwyer part in question, DH4151S, is now $81.43. I bought that part in 2015 from Dwyer for under $20. Com-Pac wanted to sell me the whole gooseneck assembly.
https://dwyermast.com/gooseneck-slide-1-2-inch-groove/
I just checked the Dwyer site, and the DH4151S slide is used on the boom and gaff goosenecks on all the catboats, PC, SC, and HC.
Yep, can't imagine it won't fit/work but I'll post a follow up after confirmation. I recently bought a pristine freshwater 2004 suncat daysailer and those goosenecks were about the only parts that were not in great shape. At at over $80 ea. from Dwyer I was going to otherwise make do...