Jim L is correct IMO,lots of those may have a bit of fluff in there (trade $$)too.
You may want to check RIA they had several 28's in the last auction (1577,1578,1580) and at least one 2 barrel set (1583)
Also note lots of single triggers are available,if yours is DT Straight grip there are not many around and it will command a bit of a premium.


Hillary For Prison 2018