Realized I had a Am. Insulator Co 145 that also had a "V" on the dome ( though the domes are of different profile), it's an [040].Put tape across mold lines and took pic. The placement seems to fit. I suppose if this is a damaged piece, the R could've 'broken off' while grinding, but I have my doubts. Any help would be appreciated. Mike

Paul Greaves responded, thank you. Damaged. Base is definitely ground in some way, no way to know if done at factory or not, but none are known to have been intentionally made that way. Coincidences aside, I can't even assign it an IEN. How many licks does it take to get to the chewy center of a tootsie pop?