The "dash" numbers on S&W revolvers indicate a design or engineering change. In the case of your 28-1, the extractor rod was changed from a right-hand (on the "no dash" version) to left-hand thread; this was done in 1960 and was also done to most other S&W models around the same time. Other parts not involving the extractor rod from a "no dash" should work fine, as should virtually any parts for a -2 or -3.
With regard to rarity, the 28-2 came out in 1961, so it's probably true that there were relatively few 28-1s made. I'm not aware of any particular premium for the 28-1, though it's certainly true that some particular "-X" versions of various models are more desirable than others.