No; headlight power is already routed through an OEM relay which controls high/low beam operation (as long as nobody has rewired your car). I have a '68, run 80/100W bulbs and have had no issues in 17 years. FWIW, I also run a pair of Cibie 45's running 100W H1's connected to the high beam power source via an add-on relay.
Of course there are others who will say relays are cheap insurance to protect the contacts in the headlight relay...