When did Parker introduce Vulcan steel?

[Aaron.dugger]

Thanks
The rib is clearly marked ( Vulcan steel ) & the serial numbers all match.
I'm assuming they probably sold a few before the started advertising.

[Pa SxS]

It's not uncommon for a higher grade to have Vulcan barrels. The original barrels could have been damaged and Parker would have used Vulcan barrels as a replacement. Quite often higher grade guns have had a 2nd set of Vulcan barrels added. Vulcan barrels were cheaper in price than Titanic/Acme/Peerless/Whitworth barrels.