[ithacaartist]

I'd say around a half hour, tops, to swap the parts you've described. This presumes basic familiarity with the process, and a bit of mechanical ability and sense. It is not very difficult. If, by "safety bar", you mean the dealie that blocks the sear when the safety lever is turned to the "safe" position, you'd need to tap out, from above, the retaining pin for the safety lever itself. With this removed, and the lever lifted out of the way, the bar is free to slide out of the frame.

Just ask what the value range is, and you'll get responses here. I think a consensus on the forum is better at valuing a gun compared to just any random "gun dealer". I'd throw you a figure, but there are others that know better what it is worth.