Congrats on your new TDS460A. Sounds like a bargain.
As far as whether a late-90s unit will be free from the capacitor issue, I can only say that my TDS460 (not "A"), with a build date of Nov, 1992, had the capacitor leakage problem. Some traces on the ACQ board were in rough shape, but it was possible to clean, repair, and recap it without too much bother.
If your caps have not leaked, it is pretty easy to remove them and replace them. Once they have leaked, things get trickier. It might be worth doing the replacements now; IIRC the cost for a complete set of new Nichicon caps from Mouser was less than $30.
A couple of other repairs were needed on my scope; they might or might not be something that could show up on your '460A. First, one of the electrolytic caps in the housekeeping supply section of the main switcher went open circuit (no leakage, interestingly enough). This made a couple of the negative supply outputs to go way out of tolerance. An easy fix, as it turned out.
The other issue was that the optocoupler used in the soft power ON/OFF control if the switching power supply degraded to the point that it was apparently trickling charge into the base of its output transistor, so that the coupler never really turned off all the way. That was reflected in erratic behavior of the front panel PWR pushbutton. Another easy fix, after which the scope settled into working reliably.
BTW, I put my TDS460 on eBay a couple of days ago as part of a lab clean-out effort. It is listed with Best Offer enabled, and I would be please to extend a TekScopes discount if a member were interested (item 263779628201; please excuse the plug).
