Is there something missing near #1 cam bearing or did GM just put those 2 bolt holes there for fun?
No, GM didn't put them there for fun, but they were only used in some GM marine applications using 2 gear cam drives with reverse rotation cams. Never could understand why nobody ever made a hold/wear plate like Ford's have, so you did have to fight end play on a roller. It would require a different cam gear that was cut for the thickness of the plate, but they could have sold it as a kit. Chevy ended up using them as soon as the hyd roller became standard. Alot of the later block aren't tapped, some aren't even drilled, but the area has always been there.