The second pic, the dot-matric writing on the left side of the recv'r down close to the wood line at the front of the recv'r...
That is the 'Import Mark'
That was mandated as of 1986 by Fed Regulation.
So the rifle was imported into the USA after that time.
Likely in the 2000's as the use of the Dot-Matric type Import markings didn't come into common use till them.
The Import Markings gives you:
Who Imported the rifle (C.A.I (Century Arms International in Vermont)
The rifles Mfg'r, Model and caliber (Chinese Model 53, cal 7.62x54R cal)
The last line is the 'new assigned ser# at time of importation'
That new ser# is the one that was used to sell and transfer the rifle in the USA and should be used in further FFL transfers.
The original production ser#('s) you see on the top of the rifle just ahead of the recv'r are actually stamped upon the Bbl.
So in BATF legal terms they are not the rifles serial number as they do not appear on the rifles Receiver/Frame.
The other ser#'s you see on the trigger guard group and bolt are just that, parts ser#'s of misc parts from other rifles. Mismatched to assemble the rifle. Common on these as stated above.
Looks like decent condition. Still has the folding bayonet.
With a good bore, I agree on the $400 to $500 range. Depends on how quick you want to sell it.