Remington Model 600 Serial Numbers

I've come into a Remington 40-X SS 22-250 27 inch barrel woodstock rifle with the serial number 33370B. It is straight factory and on the barrel is '22-250' with the 'heart' sign and on the other side of the barrel is the REP in a circle. No other markings
It has the holes for scope blocks.
My friend ordered it when he lived in another state and he moved to this state in 1973 or close to it. He is getting rather old and can not remember the year he ordered it or what he paid for it.
I've been to the Remington site for help and I can't get an answer. All I want to know is what year was it made.
Thanks,
Dew
350SerialRemington Model 600 Serial Numbers

Remington Model 600 Stock

The Remington Model 600 carbine debuted in 1964, so 2014 marks the 50th anniversary of its introduction. It was the son of the XP-100 pistol that was introduced one year earlier in 1963. The Model 600 shares these features with the original XP-100: - A new, short action - A vent rib on the barrel - A “shark fin” front sight. Fortunately for collectors, it is not difficult to determine a rifle's age, as beginning in 1921, Remington began imprinting serial numbers on the barrel of each rifle it produced. These numbers – along with some basic knowledge about the rifle model itself – is all that the collector needs in order to determine the age of his rifle.

Remington Model 600 For Sale

  1. Remington 600 Montana Commemorative- Mfged for Billings Hardware -Billings Montana. Number 1 and 2 had Deluxe high finish wood Number 1 was presented to the Governor of Montana and Number 2 was presented.
  2. 600's with vent ribs came in 222, 223 in very limited numbers, 243, 6mm, 308, 35 Remington and the Magnum version with laminated birch/walnut stocks in 6.5 and 350 Remington magnums. I have only seen the Mohawk versions in 222, 243 and 308 but perhaps some 6mm may have been made.