I doubt that you are in over your head. Before you do any finishing on it, mount the stock to the gun and check for acceptable fit. A lot of these "fully inletted" jobs need some hand fitting before anything else is done. A little scraping and sanding may need done first. At any rate, take your time and go slowly, checking final fit often. You may then go ahead and start your finishing. Some perfer an oil finish, some an epoxy or polyurethane finish In either case, follow directions closely, and don't rush the drying time between coats. Use light coats to prevent runs and sags. Keep the area as dust free as possible when applying a new coat to keep particles of dust or dirt from sticking to the wet coat. You can produce either a glossy finish or a satin sheen with any type of finish you apply. Have at it, and take your time...