A thing to remember here is that probably every classic bike manufacturer (and probably moderns too) did not make ball and roller bearings but simply BOUGHT IN AND USED BEARINGS ALREADY LISTED FOR OTHER PURPOSES.
So. Quite commonly, any decent bearing stockists can usually supply a matching bearing if you have the old one with numbers on it.
As far back as I can remember, I have never bought kits of bearings or bearings etc. packed in vehicle manufacturers boxes (including cars). If you do you are adding another agent (the vehicle manufacturer) into the cost.
The latest bearings bought from my local (general) bearing stockist include Triumph 5TA (1959) front wheel bearings, A Triumph Herald (1968) gearbox bearing and wheel bearings for a 1951 Austin FX2 Taxi. Oh. And a few oil seals too! Surprisingly cheap as well. The same man once supplied me with a water pump bearing for a 1.5 BMC diesel, unobtainable at any price from BMC dealers (though a kit was available for about £50 and a re-conditioned pump for £110). He charged me £9!
Jim.