That looks nice.Looking at your serial number and mine Im wondering if the early dating could be the following,
First 2 digits could be the week or month and the third be the year which would make yours either week 11 91 or as youve been told(more likely)11th month 91
The only problem with that scenario on mine is it would be either week 30 89 but it falls apart a bit if the first two denote the month.Being as mine is definately not a 93,the only other number which could represent a yar is the 9 which as raymondluxuryyacht mentioned would make it a 90 or earlier,possibly 89 sold in 90.Its amazing the stuff you think up when youve got time on your hands.
Incidentally while looking earlier I noticed that the cable routing on the rear seatstay is not on top of the stay,Its actually nearly underneath it,not sure if this would help with dating though.
How big is that frame by the way?