All 80's had a safety, the MK1 stock has a glossier, reddish varnish imho which sets off the grain a bit better than the later HW's

As for power most .22 Mk1's I chronoed back in the early 80's made 14-15ftlbs, before HW/Hull started putting a weaker spring in the .22's. If you look at the parts diagram in the early instruction booklet it makes mention to two different Joule springs.