Hmm, done some additional digging here, early Special's did have rounded wingtips and tail surfaces (along with open cockpits - although most of those still flying have been converted to a 'closed' format) as does the current Eagle which is, essentially, a kit version of the Pitts. Both types are offered with a range of powerplants which accounts for the differences in the cowlings between some aircraft. If the first plane you posted is an early one, then it's been retrofitted with clipped wingtips - I guess this is to increase the roll rate, just like the clipped Spitty. The second one definitely looks like an early variant to me.
Not disputing the accuracy m8, ISTR reading something about that somewhere, just thought it looked a little different to what is normally seen. Oh, and I'm right with you on the side windows in the A26 - grrr. There was one at Duxford in 2000-2001 with the low-drag turret and the full works - looked the business, and the pilot really blasted it round the circuit - seriously quick for a large® aeroplane. I'll have to see if I've any photos.
~S~ Jabo