My first search came up with a lot of fluff, but I did another and found a very helpful thread here. Also looked more closely at both sides of the bike while stripping and cleaning. It's a Super Gran Tour XV (I remember enough Roman numerals to understand that means a "15" speed, which it was). The frame is Ishiwata 024, but I now doubt that the fork is, it looks weird not only cause of the "open C" forkends, but also has a .875 steerer with a slot cut thru the threads all the way thru the column in the FRONT, instead of the more typical GROOVE cut just thru the threads in the BACK. Headset is marked Ross Professional, and seems like a standard steel FRENCH HS with the toothed washers. The weird forkends also have a US patent number stamped on them...funny that they never caught on since Ross spent the money patenting them. Clearly it ain't a Signature, and judging from the dates on some of the components it's likely an '82. I may sell off all the Shimano 600 Arabesque stuff as my co-worker probably wants more modern components that have less "snatch appeal"...and one crankarm is toast anyway. Thanks for the help!