Harry,
The 1-11 did, of course have air stairs front and rear except for the so-called Super 1-11 of the well known Big Airways. Their air stairs were not fitted (at extra cost) and weights were put in their place for balance reasons. Apparently this was due to the step-pushers union having to be mollified. They were very powerful in those days. Neither did they have water injection, nor the drooped leading edge of other Operators 500s. Super?
There was also the alleged and allied story of Boeing not allowing BA to call their aircraft the Super 737 due to potential problems with other Operators! Just a spot of info I picked up from the BAC pilots course at Weybridge in 1970.