The Super Soaker 50 had a re release for the 20th anniversary back around 09 or 10. I know little about it's specs compared to others myself, but I don't doubt OP. It desfinitely was not 100% the original reissued, it had definite changes made, the most notable toi my knowledge being making the resevoir non removable and adding a fill cap.
It also marked the final Super Soaker before the brand became a part of the Nerf brand.
When looking for old soakers, if you follow the modding soaker community and read through tons of archived posts you can find that just about every soaker has had someone post dissasembly and ideas if not how tos on how to replace or fix parts. So my personal opinion is if you really want an old blaster don't be afraid to get it if broken as long as the price is VERY low, and work on fixing it. PVC pipes and other plumbing supplies really all you need for the most part.
I recommend you keep an eye open at yard sales for CPS 2000, the very first CPS and most likely the very best one. It was extremely powerful, and while they did not get any serious legal cases thrown at them, they did take 2 years (96-98) before they released the next CPS guns and they were noticably weaker. Still very powerful guns, it's like saying silver is less valuable then gold, it's still amazing to have. Just less amazing.
All CPS guns will be at a greater chance of degradation then non bladder using guns, due to the use of the rubber bladders.
And don't expect to have these things resell for a fortune. The people willing to pay a lot of money for these things are also VERY well informed and often will not pay over $100 for most blasters because they know the proper values and where to get cheaper.