over the years many, many folks put adjustable rear sights on the 'standard autos' and can usually be spotted by the TALL front sight blade, NEEDED, to get the gun to shoot "point of aim" and then there were aftermarket adjustable "low profile" (LPA) sold by Brownells, Midway ,etc and used the original front blade and they work........
yes, if the receiver is NOT marked on the right side , rear ( left of the ejection port) as a Mark , then it cam as a standard or if the rollmarks are NOT there,may have been refinished...........then you need to also measure the overall length of the barrel,,,standard autos did NOT come with bull barrels, or tapered bull barrels..........just 4 3/4 or 6 inch..............