Hello Dave,
My boat is a 1985 tartan 34 Mk 2 and also hull number 5. I purchased it little over a year ago, and have been refitting since. The variation in L series Kubota engine appears to be small. Mostly was a feature added or subtracted from the basic 68 cubic inch engine block. Mechanical fuel pump comes to mind as I am thinking about it, or a forward splined crank shaft for a PTO. I get the impression Universal was not to particular on which block it used to add its marine components. For example on page 4 of the M-30 5424 parts manual you will see a reference in the exploded view to part #22 "hour meter assembly" you mostly likely do not have that device on the front of your engine, rather like me you have a raw water pump.
I would not assume your Hull 5 T33 has a D1102, it may have D1101. There may not be any difference concerning basic basic parts and gaskets. Water pumps seem to vary widely and having the right block to tractor connection could save some time and money. That is why I included the picture of my blocks model number. (it actually the full serial number) It took a few minutes with a wire brush to clear away the Universal bronze, and kubota blue, to get the number but it is a worth while endeavor.
So if you are facing the engine from the cabin on the left side is the injector pump and you will see a small valve (very useful when venting post filter change) directly under that valve on the flat surface the injector pump is bolted to is where you will find the kubota block number. David Leonardi Solomons, MD