Your certainly not an idiot John, idiots don't ask questions ;-)
Whilst there are different sized nipples (old cars, Morgan era cars and trucks for example) for all intents and purposes they are all the same for your requirements. The difficulty is the gun has to 'latch on' (apologies to all feeding mothers) and the gun end is sprung loaded, on good guns its also adjustable but don't worry about that for now.
The trick is to line up square and push fairly hard and the guns connector will be felt to 'click' on. the problem with the stubs is the damper is in the way.... there is a simple trick however. the lower fixing (9/16" AF spanner size)nyloc nut can be backed off or even removed (not really required) so that the damper body can be pulled, or levered with a large screwdriver forwards to give clearance for the gun. Also try it with the steering on different locks as that helps move the damper away a fraction. if you can get some angled nipples they help a lot also.
Once its locked on you can pump away and the action of greasing helps the connector grip. To remove the gun you often have to tip it through a few degrees whilst carefully pulling away. If you have a quality gun like a Wanner (best on the planet)most have 2 bleed nipples, the one on the back of the gun is for bleeding the grease chamber, the one on the top is used to reduce the hydraulic pressure and help removal (a lot don't realise that ;-)).
You will save yourself hundred and hundreds of pounds of premature wear and stiff steering with regular greasing, once done its a simple process and you will develop the knack, some fit remote greasers but many like to get under and take a couple of 1/2" AF spanners with them and do a quick spanner check whilst your down there. Morgan's respond well to TLC and maintenance and its fun to do! Honest ;-)
