Bear Polar riser initials (No interest?)

[coloradodreaming5]

Greetings all,
I recently acquired what I believe to be a 1959/1960 Bear Polar (red glass belly and back, 64" semi-recurve, I-beam riser, light red and off-white phenolic tips, feather arrow rest, exactly like what was on the cover of April/May 2008 TBM ), in very good condition, and a great shooter at my 27" draw.  

The riser is marked (all original) JH390, 64", 46# @ 26"  Below all that is a "D."  Looking for some insight from the Bear experts here on maybe why this particular bow was noted at 26 inches (instead of 28"), and what the "D." might stand for (display? demo?....).  Thanks in advance for any assistance.

OK, I'll try to dig it up on my own, and get back to you all regarding the "D."  Thanks anyway.

[2treks]

TTT