You have a 5" PC627 - and lots of goodies! The 627 Pro is only made in the 4" barrel length. Your front sight is a 'Classic/DX' style, ie, it is spring loaded. Look at the securing roll pin - close to the muzzle, like yours, means it is the easily changed version. If it was ~40% back, it'd require a pin punch, different sight blank, and careful drilling. On your version, just push hard backwards on the sight - then rotate the front up to remove. Sometimes the replacement's sides needs a touch on a 1,000-2,000 grit SiC paper to 'fit' it, although none of the sights I've used have needed it.

The Ranch Products moonclips - 50/$50 or 100/$75 shipped - work best - actually can be finger loaded - with Starline and Remington brass. Congratulations - great find! It does need some nice Ahrends cocobolo stocks, however...

Stainz