Cam machined area

[No Quarter]

On my 64 3.8 I had to replace the cams as the engine has been sitting for 20+ years, no oil, not turned, or so it looks. Just wondering. The orig cams are nearest, with red paint. The new ones I'm considering to replace them with, on the nearest one, right behind the first lump, there's a wide machined area. What is that area machined for, does anybody know? Does it tell me something about which engine these cams came from?

[Jack the lad]

I cannot get a good look at the machined area but it looks pretty rough and not like the rest of the cam lobes. Could it be that they are from an XJ6 or similar low output engine and the seller has ground the part number off to enable them to be sold as E type cams?

[mgcjag]

C17138.. look at the cam part number..not the forgeing cast number....its very small and on a flatted off area..possibly on those shiney areas....however have a look here..3.8 cams with the same raised machined area https://ebay.us/m/cq7L2c

[No Quarter]

Jack, I don't think so, that area is 1 mm higher than the rest of the (rough) camshaft
Steve, that's like the ones I have

Thanks, was just curious