the short answer is no. The 459156 cam is for the Lucas
K1F model 42183 E/F used on various Panthers from '49-'57. The 459321 ring cam is for some of the competition versions of the Lucas
N1, namely the NC1 & KNC1 used on some BSA Goldstars, AJS, Matchless, & Royal Enfield single cylinder comp. bikes for 1957.
The correct ring cam is available, I order mine from a manufacturer in the UK. Because I rebuild Lucas
& BT-H magnetos & regularly order from the UK & can get you a price if you wish.
Please contact me off-line if interested, otherwise one may come up on eBay
All the best,
Home of the Easycap magneto condenser, over 5,000 on the road without a failure !!!