Dab of oppo : There is no part number, it is a custom order to Moto Lita with the below description :
" 14” 4 Spoke Black anodised Morgan wheel, slotted spokes, flat, black leather rim with thumb grips. Bolts directly onto original boss "
Hope it helps.
I found the standard gear knob too "modern" with the transparent diagram on it, the sparco is very nice looking and more timeless.