Which color is it? If red, maybe, If any of the other three colors, no. But be aware of the down side and the costs. Others have given you lists of costs, but I didn't see cables mentioned. A good cable set will set you back $25 if you shop wisely. Less if you buy in bulk quantities.

The only reason why I would rebuild this bike is that the frame has an attractive appearance. Especially the red. That's why.

The two reasons why I wouldn't touch a Raleigh Grand Prix from 1975: steel rims and cottered crank. The rims won't help with good brake performance. The rust will clean up okay. The cranks require nearly forgotten tools, parts and techniques to remove and re-install. Not impossible, and many on the C&V sub forum enjoy having this type of vintage crank on truly collectible vintage bikes.

So, if I were to take on a grand prix, I would: replace the wheelset (or re-lace the hubs with aluminum rims as others suggested) and remove and replace the crank. Just starting out, you won't have access to these things, so would have to pay. Worth it? I don't think so. Ride what you have and donate the Raleigh to a coop. Take the deduction.