Need information on a 1961 88SS

.. starting at 7,200 seems a bit on the high side. The "safe" figure that comes to mind is 6,800.
Just my opinion.

It may have fitted a 20T engine sprocket, so as well as an AMC2 gearbox (pre-fix NA) that means it will spin-up quite quickly so a 7,200 rpm red line is fine.  It will easily exceed that if you let it rev out in the third gear,  so be aware.  If it's using 650 gearing with a 21T engine sprocket it will be a bit more sedate through the gears and may struggle to reach 7200 in top.  On a good day it'll keep up with Commandos but don't sustain high revs on Motorways for long periods.  Regular oil changes with 20/50  GTX was always a good idea.  Try to ascertain what oil the previous owner is using.  Adding a good oil filter is a good idea.  They thrive on revs so don't be too gentle.  Good luck, Howard

Have a look inside the siamezed pipes where they come together.  MIne (after market) had hole size in main pipe not big enough for the slanting-in LHS pipe.  It upset carburation at high revs  and probably explains the piston damage it suffered.  Two pipes made mine run more smoothly.  Mick Hemmings (name dropping) said it was faster than a Bonnie across country with 2 up.  But he was probably faster no matter what he rode...

That converts to around £6,300.
Certainly a nice looking bike from the photos - but then they always are! 
No idea of prices in the US, but I would be surprised to see it achieve that price here in the UK. Just my opinion... 

James - as regards you asking for relevant information about the 88SS Model - here goes.  There should be a Lucas K2FC Competition magneto with an automatic advance and retard unit.  Hard  to see as that's inside the timing cover but the absence of an advance lever and cable will be the clue. The head can be a semi-downdraught unit (like the one on your images) or the previous big fin, big valve unit with a twin carb manifold.  The carbs should be paired 1 1/16 inch Amal monoblocs with one with a chopped float bowl on the semi d/d head.  There may also be sprung steel  sleeves in the inlet manifold spacers running through into the inlet track.  Some of the early d/d heads had 28mm ports but most had 1 1/8 inch ports. The tacho on the early bikes had a chronometric instrument mounted on a bracket arrangement with rubber cushions.  ( As in your image) .   The silencer on the SS is round rather than the later or earlier cigar type.
In spite of it being a 500cc twin very little in the 88SS engine is shared with the standard 88.  Most of these items are hidden from view but here you go -  Crankcases, crankshaft,  camshaft, cam followers, cylinder barrel, pistons, pushrods,  cylinder head, valves, valve springs, oil pump, exhaust system, timing cover, carbs and magneto are all different on the SS.  The gearbox is an AMC2 (pre-fix NA) and the clutch is the 11 plate SS variety.  Only the con-rods and timing gear/chains, bearings and seals are shared.  The early ones have the narrow short Roadholders and the drive chain and sprocket are 5/8 inch X 1/4 inch. They are fantastic middle weight bikes.  Cheers, Howard

According to Bacon, manual advance was specified originally, but auto advance from 1964.  My 1963 has auto advance with K2FC magneto.
Auto advance theoretically should give slightly easier starting because contacts always open at the 'sweet spot' where magnetic field collapses.
The road test report from Motor Cylng May 11 1961 is enthusiastic.  Not many of us in Britain today would run up the motorway at 80 to 85mph.