Scottishgourmet.com has a couple of pretty good offerings. Their puddings and haggis (no lungs) is made in the USA. I’ve no experience with what the authentic Scottish products taste like— but these seemed good to me.
I’ll check it out. I usually have black pudding during bk’fast when I’m in England. I did try haggis in Scotland but if you’re going to eat in a pub, take my advice, and skip the haggis.