Liner in an original Steven Ideal 44

[Fogman01]

I am looking at a BPCR silhouette rifle for my wife and saw a Stevens Ideal 44 with a 24" half octagon barrel in nice shape except the bore is "fair". The gunstore said the bore would not be up to target shooting. They said I could put a liner in it. I hesitate to mess with an original rifle but is this something that could make it shoot well and be an acceptable modification to an original since I would not be changing the caliber? He wants $1500 for it now.