12volt vs 6 volt Coil in 6 volt System

[dorvedahl47pu]

I've got two 1947-late Ford pickups. Neither has the ignition resistor. So, I'm looking for 1.5 ohm coils. I ordered one off Ebay from Third Gen Auto. The ad said it was a Petronix, 6 volt, 1.5 ohm coil. Cool, that's what I wanted/needed. So, it shows up and I do some research on-line with the part numbers (B-12000 and # 40011) it turns out it is a 1.5 ohm 12 volt coil. Should I care? Will my 6 volt positive ground system work properly with this 1.5 ohm 12 volt coil? Thanks.