admiral 22x12 and 12lp4

[wiseguy]

hey guys and gals(ya never know),i recently picked up a admiral
22x12,and found the crt is a RCA type replacement or rebuild,it has tags all over it and with a date of manuf of 1958,but this tube looks aluminized..??were these tube rebuilt this way?
i was not sure to restore or trash,the bakelite cabinet is great,chassis is dirty,full of yellow stuff,but comes off,i got half a raster but is too bright and well focused for a 12lp4,then i noticed the aluminum coating around the tube inside,it has an ion trap but i didnt try it yet with it off...i don't know the year of this set,but the I.F section is shielded pretty well,and has the correct tuner..(sigh)
if you look closely at the pic below it shows the crt not fitting the masking correctly,am i missing a gasket..?
thanks
terry