I think we need a bit more info to ascertain if theses barrels were indeed cut or not and if they had choke in the first place. Holland was certainly keeping detailed records in the late 1890's and the OP says that it was made decades earlier. if it was indeed made in the late 1870's, than why would we assume that it had choke in the first place? More than likely, it did not.
Just because it has barrels of an odd length does not mean that it was cut either. They are still almost 30" which begs the question - cut down from what? The chances of the barrels being more than 30" on an H&H of that period are slim.
Do the barrels touch at the end and have a small flat between them?
Is it possible to get a photo of the end of the tubes?
Did the original ledger entry have the date it was made?
If it did not have choke originally and you want to sell it, do not add choke as it will kill the collector value if it has any. I would suggest selling it and buying something with the chokes that you want. If you want to keep it forever as a shooter, then do as you please.
