The 088 was made from '79-'86 by H&R Inc who went bankrupt in 1986. SB1s are made by H&R 1871 from 1987 on, probably not a lot of difference between them both being cast iron. SB2s are only made by H&R1871, they're heat treated investment cast allow steel, made for non-magnum high pressure rifle chamberings such as 270 Win. H&R won't fit barrels to anything made before 1987, but you may be able to fit them yourself, see the FAQs.
Tim