Rather upmarket from the a model presumably there was also an early b model but i ve never seen or heard of one.
Serial number yashica mat.
Next is mtl 4110xxx and two with mtl 5080xxx numbers.
Camera mtl 4021xxx has 285xxx lens numbers which look like they are from 1961.
This model was made from approx 1970 1986.
Very few mentions of the production range online and the existence of the massively popular later 124g model makes finding information about the plain old mat version difficult.
The serial number was the key though and it appears that serial numbers exist going up into 1973.
Typical taking lens serial numbers from to 66 series pigeonflex 215xxx 255xxx 18 244xxx 269xxx yashima flex 37xxx 44xxx 6 272xxx 285xxx yashica flex b 4xxxx.
Bay 1 mount for filter hood tele and wide lens adapters.
Yashica mat lm lens serial numbers are very consistent and these look like they are from 1960.
The yashikor lens was supposed to be an improvement on the yashimar but i suspect there s little difference both being rebadged tri lausars from tomioka.
Film tlr 6 6 medium format 120 12 frames or 220 film 24 frames built in light meter.
Based on that site i believe the serial number of my yashica mat dates it as having been produced in january of 1971.
The next example is mtl 4012xxx with lens numbers both 368xxx which look like typical late 1962 numbers.
The sources i could find said it was made until 1971.
You can refer to the table below to check about the date of your yashica tlr source of table.