Keep in mind, Lew Horton is simply a distributor/middleman. They are not gunsmiths or tuners. There will be nothing on the gun or box to distinguish them in most cases.
That said, I do believe the other poster is correct that there was a limited run of 3" unfluted 29s about 1989 ordered by Lew Horton for distribution.
If it has the original Goncalo Alves finger-groove combat grips, and is NIB, it could fetch $800 to $900 in a strong market (this one is a little weak, though, right now). Those grips tend to add $150 or more to the value of the 3" N frames.
Bryan