Hi Jeff, thanks for your message. If it’s a Reynolds frameset, the decal is one way to tell whether or not it’s butted. For example, the brands featuring butting tend to have decals which say ‘butted’: https://h-lloyd-cycles.myshopify.com/collections/reynolds – however, if the decal does not say ‘butted’ feel free to email toptubes@reynoldstechnology.biz with a picture of the frame and we can try and advise. Kind regards