Yeah, I'd want detailed pix of the top tube before buying any steel bike set up for triathlons and time trials. Lotta sweat and salty electrolyte water is gonna hit that top tube and rust if the owner wasn't meticulous about wipe downs.
The tube integrity is probably fine. But it'll take some work to make it presentable. The price would need to be really low to tempt me, since I'm not sure I'd use the aero bars. Although I might swap the bar end shifters to the drop bar, or maybe even convert to a faux-path racer configuration with flipped albatross or North Roads bars (one of my maybe-someday wishlist projects).
And since I have in mind a faux-path racer, a frame with a little rust might not be too bad if it hasn't affected the integrity. I'd paint it black anyway, maybe with some subtle decals or lining of my own, rather than worry about keeping the Ironman originals.
Despite my nitpicking about Suntour GPX Accu***** indexing, the group is actually really good. Love the brakes, the aero profile and subtle steely blue just looks spiffy. I like the looks of the entire group. But it's really persnickety about chains, freewheels and setup to get reliable index shifting (which I would have known if I'd actually read the Suntour service manual that I downloaded a year or so ago -- it's very specific about how picky the Accushift stuff can be and what components it prefers). I finally got mine dialed in with a SunRace 13-25 freewheel (smoother shifting and quieter than the original Suntour Alpha 13-24), and KMC Z51 chain (Z72 was good too, although the mushroom head rivets seemed to loosen up a bit and get noisy with wear). Loosening the cable/housing loop around the rear derailleur helped. When I replaced the RD cable/housing I added about 1/2" or so over the original length and it seemed to help with index shifting.