Yes I can tell that your bushing is aftermarket. The hex bolts appear to be almost correct dark shade..Probably should be darker like phosphate. But if your perches are still early then you would need to put Cadmium bolts. In a rare occasion phosphate could have been used depending on the month of transference. The redesign of the bushing in 1967 would use phosphate/manganese bolts. My bolts will need to be Cadmium plated but I still don't know how to put perma-blue on the bushing. Does the bushing need to be taken out or blue it the way it is installed.
Being an early 67 Mustang you have 2 welds holding the bushing for extra protection.
My early bushing has Factory markings even through the ends have cracking as is expected. Also the rubber ends had black paint and that deteriorated the rubber more. I did find some remnants of yellow paint on the rubber.