Dating a JCM 2000 DSL

[D28boy]

I've just bought a JCM 2000 DSL 100 watt with a serial No of

M-1998-24-1434-A

Does this mean it was made in 1998?

Also notice that it has two pairs of different make power tubes could this be a potential problem for the amp?

[surfnorthwest]

In 1997 Marshall changed to the latest date code system. It is very easy to read because the year is directly followed by the week.

For example:1999-22-1349: Year of manufacture is 1999 in the 22nd week.

[surlybastard]

Is the third number which exact unit it was during that week?