Correct Spark plugs?

[Freddo]

Hi,
I have owned this 1967 Chevy C 10 for several years. It is or at least appears to be mostly original. It has a 283 and I am getting ready to give it its first major tuneup. I ordered the tuneup supplies from rock auto and ordered the AC Delco R-45 plugs. I am removing the existing plugs and see that they are quite a bit different, the threaded area appears to have more threads and they are longer. I did a search on spark plugs here on this site but didn’t see anything that referred directly to this. I included a picture of the two different plugs. Can you tell me if it is OK to use these R-45plugs in place of these old plugs?
All help appreciated! Thanks!