If you are unscrewing the tub drain to take it out, be careful with the plumbing directly under the drain that sits in the little plastic bucket thing. That one piece is very hard to replace with anything that is currently available. Ours had a crack in it, and we spent much time and money looking for something that would "work". Short story.... plumbing speciality place in Kansas City had to special order it.
Just be careful ---- "if it's not broke, don't fix it"
Beth and/or David
67 Sovereign, double bed, rear bath-"Moby"
2005 Dodge Ram 2500 Hemi, Quad Cab-"Ahab"
"Vintage trailer, vintage owners"