They still test if you want regular tags (which I prefer), just not as thoroughly.
Yeah, '73 you're good. My '74 is rock stock (including emissions equipment that may still function), but would have passed easily without. On the whole, emissions equipment are just devices that make the ability maintain and tune a car less than necessary (though there are exceptions). You can have a crappy tune and still be relatively clean running. When I had mine tested the HC limit was (and I'm sure still is) 1000 PPM... I came in at 14 PPM. This was tuning by ear (though I was a little lean in the slows).
If you tune it anywhere near where it should be, you shouldn't have any issues whatsoever. I'm hoping to start a wideband revolution in the LC universe, but need more fuel economy data to make my case as the subjective benefits (performance, engine note, feeling of satisfaction knowing that your machine is as good as it can possibly be) are not very communicable. I have been getting 14 mpg with locked hubs and nasty weather though, and I think 15 mpg will prove the average 9 months out of the year. Not great by modern car standards, but beats the hell out of the 11 I was getting and the single digits I keep hearing about.