Properly bedded and pinned, they'd not need the extra recoil lug. It depends somewhat on the loads and stock wood, Rod.
I put an extra lug on my first .375/06IMP. The stock was a soft piece of beautifully figured claro - the more figure, the softer the piece, I guess. It was a Fagen Reinhart stock and used to break every 1,000 rounds or so. The lug was after pinning behind the aciton lug and through the wrist - still used to break - different place very time. It was a fast barrel and turned in exceptional terminal ballistics. The splitting about drove me crazy - never broke with the .458 2" barrel on it and I used to run 2,060fps with 510gr. WW solids, 2,300fps with 350's - those were soft in comparrison to the 510's. It's possible the .375 had a 'sharper' speed of recoil that was so hard on the stock.
I can't see an extra lug needed for 1923 9.3x62 ballistics which many people seem to use today.