rm06 , that is possibly one of the finest photographs of a H.P. ,or any gun for that matter,,I have ever seen, ( applause,.....).
Regarding the finish variations on H.P.'s the most popular theory is what day of the week a gun was polished (how good the polisher felt at the time) would make one or another shinier than the rest.
But having seen examples across the 29 years they were produced I cannot say I've noticed
any particular timeframe where they were shinier than most.
Maybe others can add their opinions
Regards ,,Al