I've a .177 scorpion here that's somehwat tatty but works fine, however it's missing it's rearsight.
I have a few spare BSA rearsights, but they all have the "pip" on the underside, just in front of the elevation adjuster. The scorpion has no provision for this pip.

Do I drill a small hole in the cylinder to correspond with the pip (my preference, as it's more secure way to moutn it), or file the pip off the rearsight ?

NB The cylinder is really quite tatty, and I actually think the rearsight is worth more than the cylinder !