Shimano 105 early- to mid-1990s SLR groupset on eBay worth it for 70s SuperCycle rebuild? Is the below groupset a good value for this frame? 

I picked up a vintage SuperCycle Medalist frame (I'm guessing 1970s) and am looking to make a comfortable but capable bike for commuting and general urban cycling. It has a few parts that I'll clean and evaluate while I rebuild, but for the sake of argument, let's say that I only keep the frame/fork, cable guide clamps, and perhaps stem.



I have found a Shimano 105 early- to mid-1990s SLR groupset on eBay for ~$480 shipped. It includes:


BR-1055 brakeset
HB-1055 + FH-1056 Hubs 32 holes laced to AMBROSIO Elite Wheelset 700C 622x13C (pictures indicate tubes and tires may also be included, although that's not a huge concern)
FD-1056 + RD-1055 front and rear derailleurs, respectively (will need a 28.6 mm adapter clamp for the braze-on FD)
BB-UN71 bottom bracket, English threading
STI-1055 shifter 2x8 speed
FC-1056 Crankset SG 53/39 (170 mm, 9/16x20)
Shimano 105 Headset Italian Thread (I'm guessing HP-1055)
Shimano PD-1056 Pedals
134 cm chain
Shimano Freehub 8 speed (13.14.15.17.19.21.23.26.) (I'm guessing standard HG50)


The issues with my bike are minor and twofold. First, my frame and fork spacing will need to be widened slightly by cold setting: from 126 to 130 mm in the dropouts and from 96 to 100 mm at the fork. Second, I would require nutted brakes and perhaps a longer reach as I plan to use 700C wheels in a bike that was likely 27". So instead of using the BR-1055 brakes, I'd pick up some Tektro R559s.

The question is whether or not this groupset + wheels is a decent value. It is attractive for me given that individual parts come with individual shipping costs and vintage/used parts are excruciatingly difficult to source locally where I live. I built a bike last year with Shimano 600 components and while the final product is absolutely amazing, the costs for sourcing individual parts added up quickly.
For not much more than that ($600 dollars), you could put a new Tiagra 10 speed group on the bike. So in my opinion, no, that is not a good price for those components. 

Even if they were unused, it would be a high price. You are the only one who can make that value judgement, though. 

Do you want the vintage look and feel? Are the components unused? Do you think it's worth close to the same money as a newer, better quality group set?

Then it may be.