As OLD SEMPERFI stated, a C&R License (FFL 03) is not necessary to purchase old firearms.
This site contains very good basic information about the C&R License http://www.surplusrifle.com/shooting...fl03/index.asp
Just as an aside. The vast majority of C&R weapons are not
Some examples of C&R weapons
M1 .30 Carbine
Every Mosin Nagant rifle ever made
Definition of a C&R weapon
What is a Curio or Relic, ala Title 27, Code of Federal Regulations (CFR) part 178, section 178.11
Curios or Relics: Firearms which are of special interest to collectors by reason of some quality other than is associated with firearms intended for sporting use or as offensive or defensive weapons. To be recognized as curios or relics, firearms must fall within one of
the following categories:
(a) Firearms that were manufactured at least 50 years prior to the current date, but not including replicas thereof;
(b) Firearms which are certified by the curator of a municipal, State, or Federal museum which exhibits firearms to be curios or relics of museum interest; and
(c) Any other firearms which derive a substantial part of their monetary value from the fact that they are novel, rare, bizarre, or because of their association with some historical figure, period, or event. Proof of qualification of a particular firearm under this category may be established by evidence of present value and evidence that like firearms are not available except as collector's items, or that the value of like firearms available in ordinary commercial channels is substantially less.