According to the RENE,,, by it's appearance,,, it'd be a model RB-44. (RB = blue, Ruger NM Bisley Blackhawk)
However, the RB-44 has a known serial number range of; 85-40742 to 85-50240.
The RB-44W, the model with the roll marked cylinder has a serial number range of; 85-47522 to 87-57402 with many thousands made.
To get the proper ID,,, a letter from Ruger would be in order. Be specific in your request, to make sure they give you to all important RB-44 or the RB-44W info. If it turns out to be a lettered RB-44,,, then the RENE gets an update.