The GPR kit is generally so finished that you could just put it together and shoot it as-is. Lots of extra wood on the stock for my taste, so I trim that down. There are a few little fiddly things to watch out for, but otherwise it's a really straight forward job.
Top of the fiddly list are the little escuchion screws, which are really fragile and easy to break. Many folks replace them with the next size larger. I simply soap them, then use a good fitting screw driver to slowly turn them in, backing off a turn any time I run into resistance and starting again to "work" the screw in.
You'll spend time filing and sanding on the cast metal fittings like the forend, trigger guard and forend to bring them to a bright finish. I enjoy that, but it is slow and fiddly work.
Best idea for metal finish is LMF browning solution. No ovens, no mottled look. Just straight forward path to a nice brown finish.
Directions in the box are sufficient but sparse. Lots of past threads here on the site about building and finishing the GPR. Lots of folks willing to answer questions, too. I'd say go for it. You'll have lots of pride in the results, and it's a great pathway into future builds, if you decide you like it.