Did Viking Detect C14 in Mars Methane?

Scientists just found Mars methane is produced by ultraviolet rays
shining upon carbon compounds (Ref. 1). As Mars methane could dissovle
into liquid nutrients in the Labelled Release (LR) experiment (Ref.
2),Is it possible that Viking Labeled Release experiment detect C14 in
Mars methane (Ref. 3) or carbon dioxide (Ref. 4), instead of C14
released by Mars bacteria?
Ref. 1:
http://arstechnica.com/science/2012/...-mars-mystery/
Ref. 2: http://en.wikipedia.org/wiki/Viking_...abeled_Release
Ref. 3: http://en.wikipedia.org/wiki/Carbon-14#In_fossil_fuels
Ref. 4: http://en.wikipedia.org/wiki/Viking_..._conclusio ns
Quote from Ref. 4: “A sufficiently strong oxidizing molecule would
react with the added water to produce oxygen and hydrogen, and with
the nutrients to produce carbon dioxide (CO2).”