i've seen people do it with large screwdriver and trying to protect the paint if not make any dents in the body, using towels, blocks of wood or rubber to spread the load. they get them off albeit with a lot of mucking about sometimes (setting up and if its stubborn). it wouldnt be my favoured way(AT ALL- too much risk) but it seems to work for many. if i was in your neck of the woods then i'd give the NPD tool a go coated with some electrical tape. there is another tool but i've only found it shipped from Australia so its more pricey! (search for "WINDSCREEN WIPER ARM REMOVER PLIERS 9" / 230mm T&E TOOLS, DALLAS") that is a reverse type plastic coated plier that is shaped to fit around the nub of the wiper. worked good for me.
the general consensus is chrome/shiny for 65 wipers and satin/dull for 66 (which suits me fine for the KISS method). but it can be more complicated than that from what i have found. some people that know their stuff (part numbers etc etc) have researched it in depth over many years (decades and several hundred examples from junk yards to NOS) others have been in the parts trade game for generations and claim to know from the horses mouth that TRICO began to change to satin/brushed from early may 65 on mustangs (another reliable source says june or july but that is based on his collecting data off vehicles over many years). there can also apparently be some differences in the transition period before TRICO had nailed down their method. so on some it is said that the outer side will be dull while the inner will be shiny, no doubt brushed or bead blasted on one side the existing shiny stock left from 65, late 66 and 67 have a more dull finish by the looks (especially at the base knuckle), compared to mid or early built 66's (i'v not noticed my self until shown an example but i wasn't looking that closely up to then)
so its said to be that from sept 64 to beginning may 65 shiny, flanged, with polished arms and blades is correct. but its probably one of those things that will never be known for sure given the time passed and other variances such stock on hand at different plants .Also it was suggested that TRICO managed to get the blades sent out satin while the arms were a little behind in development and still shiny in some instances, also on some its reported the base is dull but the rod section is still polished...yet others have insisted that their early built 66 (assume oct or so) had shiny equipment-go figure
