Dear B Sousa,
Here's some info for you but its not a NSN
blade number - this advert has appeared in the HAI magazine ROTOR, every issue, for the past 12 months:
Surplus Parts Inventory Liquidation - S-61 Helicopter Inventory - over 39000 line items - avionic & electrical, dynamic, hyd-ASE, power plant, structural - (AN + MS + NAS)- all sold with certificate of compliance - for details contact ........their European rep has a United Kingdom phone number.
I'm not a tout so there's no more info to share. But to a ground-based guy like me it sure looks like somebody is trying to unload S-61 blades.