3rd Generation, born in 1998. It's from a run of 100 that Turnbull did in collaboration with Colt from the late '90s through the early 2000's, where they would receive these guns from Colt "in the white" and finish them. They each came with a special "DT" serial number. Here's the description from Turnbull's website:
"This is a limited-edition Colt Single Action Army Revolver, 3rd generation, featuring Turnbull Restoration finishes throughout, and “DT” (for Doug Turnbull) serialization. Only 100 examples were built and finished in the early 2000s.
This example with 5-1/2” barrel features the
museum-grade metal polish and finishes for which Turnbull Restoration has been known for 30+ years:
Frank