Here's a WWII service rifle I "sporterized"....It happens to be a Mauser....I did all the work but the safety, trigger, barrel, chamber reamer. stock blank, stock routing, and misc items such as scope bases and mounts and sling swivel studs, recoil pad, Williams iron sights, barrel engraving and bluing was over $1,000

With some creative smithing your O3-A3 might turn out this nice.....but the Lee-Enfield won't!

BTW....the "so called" collectors value of the Lee-Enfield is about $150....give or take.....

It don't take long and that used Rem-700 begins to look like a bargain!