The so-called "Red Knob Twins" were made until 1994.
Check the serial number and consult the table listed here.
While doing research on Fender amps in general, and the Champ in particular, I came across the most amazing series of articles by Greg Gagliano on the subject. If you have any interest in vintage Fender tube amps, without question you’ve got to read them all.
The process that went into figuring all of this stuff out over 6 years and countless owners of vintage Fender amps is hands down an amazing story.
Combined with what we saw with dating a tweed Fender Champ by the tube chart and speaker code, I’m feeling pretty good that all of the various dating methods point to early 1959 for my amp.
Although Fender never kept serial number records of its amps, you can determine the approximate year your Twin Reverb was built by matching it against the cosmetic changes the amp has gone through.Earlier models had black lines on the aluminum control plate. From 1977 to 1982, the Twin Reverb's power was increased to 135 watts.Those manufactured in 1973 and later also featured a push-pull master volume knob.“Dating Fender Amps by Serial Number,”20th Century Guitar Magazine, Gagliano, G., March 1997, pp 28 – 29.“Dating Fender Amps by Serial Number, Part II,” 20th Century Guitar Magazine, Gagliano, G., November 1997, pp 46 – 48.