Gas chromatography has been done that shows very little difference between new and vintage Old Spice. And what differences exist are positive (greater longevity):
Will the real "Old Spice" please stand up
Abstract: Four spice aftershaves (three Old Spice variations and Vijon Spice) were analyzed via headspace-gas chromatography. These aftershaves were compared for similarities across the entire chromatogram. Based on overall similarity, it is concluded that currently produced Shulton Old Spice...www.badgerandblade.com
In India, Old Spice is licensed to various cosmetic and chemical companies- lots of different manufacturers make it, and there are subtle differences between each one, mostly in the sourcing of the chemicals.
Shulton hasn't been "making" Old Spice since 1970. In that year, it was sold to American Cyanamid, a chemical business... years before it was sold to Proctor and Gamble. "Shulton" was retained as what amounted to a brand name.
In January 2016, Procter & Gamble changed the scent of its Old Spice Classic After Shave. According to the product's website, under ratings & reviews, the change was made in order to "comply with new regulations