Don't go out and buy more chokes for that gun ....just use one of the ones you have ...make sure you like the pastime first....
Depending on how much you like this ....there can be a lot that goes into it ...for the best loads, chokes, guns, etc..../ but mostly just concentrate on having some fun.
You may just need to have some cash for shells and targets ...and borrow one of your buddies guns that are already setup - especially if they're experienced.
When I have new shooters with me....I typically provide everything (partly so I know it works ), and vests, shell holders, etc. --- not saying that your 1950's gun won't work ...but the technology on guns, chokes etc has changed a lot since the 1950's .... and I let them put some cash in the kitty to offset the expense - it also keeps this whole issue of what kind of shells and chokes, etc from becoming a distraction. That way - nobody gets a lot of money tied up in equipment that they may never use again...
I just ask new shooters to make sure they have safety glasses that fit ...and ear protection ...and I take care of everything else.
But I'm kind of like a "bad guy drug dealer.." ....now that they have a taste...they have to bring their own equipment the next time they come out to play ...!!