These came in a Merlin parts kit a long time ago. They appear to be either raw aluminum or a roundhead style that was anodized and then had a hex top added. See photos.
They are in great shape but I would likely recommend reanodizing or new anodizing.
Sold with spacer. No other parts are included. See photos. These only fit AKA Merlin bodies/front blocks and are NOT 2k compatible.