Having compared the main dimensions there for all practical purposes seems to be little or no difference.
Model: 817BUL
Caliber: .38 SPL +P RATED
Capacity: 7
Barrel Length: 2"
Action: DA/SA
Finish: Blue Ultra Light
Grips: Ribber
Weight: 21 oz
Construction: Ultralite-Alloy
Capacity: 7
Barrel Length: 2"
Action: DA/SA
Finish: Stainless Steel
Grips: Ribber
Weight: 28 oz
Construction: Steel
Frame: Compact
Front Sight: Fixed
Rear Sight: Fixed
Trigger Type: Smooth
Length: 6-5/8''
Width: 1.531"
Height: 5.10"
Rate of Twist: 1:16"
Grooves: 5
617
Frame: Compact
Front Sight: Fixed
Rear Sight: Fixed
Trigger Type: Smooth
Length: 6-5/8''
Width: 1.531"
Height: 5.10"
Rate of Twist: 1:16"
Grooves: 5
Granted the 617T is Titanium, but the dimensions are still the same for the 817 and the 617T. The only caveat is the cylinder is going to be slightly longer in the 617T by hundreths of inches due to the magnum chambering over the 817UL in .38 Special. So there may be some looseness. Overall though holsters for one should fit the other.
www.kdholsters.com might be able to help if you contact them.