I read it as you must have the anticollision light. We had to install
it on the Cessna 140 for this reason too. I think the only difference
is that you have more choice in color because of your age. I don't see
anything here that counters the statement "An approved aviation red or
aviation white anticollision light system".

91.205.(c)
(3) An approved aviation red or aviation white anticollision light
system^M
on all U.S.-registered civil aircraft. Anticollision light systems
initially^M
installed after August 11, 1971, on aircraft for which a type
certificate^M
was^M
issued or applied for before August 11, 1971, must at least meet
the^M
anticollision light standards of part 23, 25, 27, or 29 of this
chapter, as^M
applicable, that were in effect on August 10, 1971, except that the
color^M
may^M
be either aviation red or aviation white. In the event of failure of
any^M
light of the anticollision light system, operations with the aircraft
may be^M
continued to a stop where repairs or replacement can be made.^M