This is a much better example, just scroll down to see it. They also give important information on the type.
These are demanding pretty good prices, and this one is $ 5,364.00
RARE AND ORIGINAL DUBLIN CASTLE BROWN BESS FLINTLOCK MUSKET CIRCA 1795
A rare Dublin Castle Brown Bess Flintlock Musket. 39" barrel in very good condition with proofs and inspectors crown mark between, regulation .75" bore, foresight/bayonet stud. Lockplate and furniture with no border line engraving (as noted on later genuine Dublin Castle locks) with DUBLIN CASTLE engraved to tail, Crown over GR under pan, Swan Neck cock of 1793 pattern, all original with excellent patina. Feint but distinguishable 4 on inside of lockplate immediately to the right of the mainspring to bolster attachment screw (4 with a crown was the Irish inspectors stamp/number as noted by Goldberg and Mowbray book, page 83, of "The Brown Bess"). Very strong working action. Regulation 1793 brass furniture marked 1/17 to the buttplate tang with the Dublin Castle feature (seen on the handful of these 39" muskets surviving) of a flat sideplate (as opposed to rounded/raised on normal 1793 Pattern) marked PATTISON. M. J Pattison was a Government contractor who had a business in Dublin c1790-1840. Good original stock with general handling marks, some old filled wormholes, minor infill repair to left hand side rear barrel pin area, old repaired crack between lockplate and triggerguard. Iron ramrod looks to be original. 55" overall length.
https://historicarmsgallery.co.uk/longarms-and-blunderbuss