['ol Pinion head]

personally have had in my hands:
-an original GM vendor manufactured dual snorkel 2nd Gen T/A original tab shaker base with only one heat riser (no heat riser in the passenger snorkel). The spot welds on tabs & passenger side snorkel were bone stock/ I know EXACTLY what those look like as I've restored quite a few very hard to find original dual snorkel aircleaner bases. That was over 20 years ago in Ft Worth & I looked the aircleaner assembly over very closely. The red '73 auto T/A that the air cleaner asm was removed from (in front of me) had the factory die stamped ear style retaining section & had factory rivets attaching the fiberglass top. There was no structure for functional solenoids to mount to, nothing had been cut, this was NOT an earlier functional shaker top. The only thing non stock appearing was the thin rear steel plate had been removed & a piece of metal screening had been cut & glued into the rear of the shaker top. Very common to see opened shakers with screens on '73 & '74 D-port T/A's. Through out the 80's & 90's I def ran across more '73's & 74's that had their opened shaker tops fastened to the hood with thin metal brackets. Typically, a Pontiac Torquer intake & misaligned small aftermarket aircleaner base lived under the hood. Nearly always being fairly common D port automatic cars, I never paid much attention to these cars. Given an X in th VIN, or a factory 4 speed, my "antennas go up".

-Several years before encountering the red '73 auto in FtWorth, & its long time owner, I owned a near identical non functional shaker top (faded & scuffed Brewster Green finish) with no solenoid attachment bracing. This shaker top also had the factory bolt down flanged area along with factory rivets holding the shell which I drilled out as the fiberglass shell top was seriously damaged on both front corners.

-early 00's I bid on eBay but did not win the auction on another tab style no solenoid mounting provision '71+ factory shaker top. Was not a thin shell '70 shaker but later 71+ thick shell top..

of interest, several early functional twin solenoid style shaker tops have also appeared that did not have the factory die stamped ears for attachment, but had the later clamp style attachment. One such shaker top was recently on eBay & definitely another odd piece, I don't believe it was created using the limited production 90's parts kit.

Aftermarket parts wise:
-am fully acquainted with the previous parts kit that PY was selling in the 90's to convert non functional shaker tops with a die formed brace, T rod, black plastic end frame & steel rear flapper. It took some really nice TIG & finish work to weld the brace in. the previously damaged Brewster Green shaker top that I mentioned swapping fiberglass shells on, also gained a set of those parts, a pair of NOS solenoids & repro harness in building a '71 functional shaker top.

-Last, Joe @ the Parts Place $298 repro shaker base that Mike referenced in his OP. Very easy to notice it only has one heat riser attachment, not correct for '71-72 T/A usage. Also obvious the stamping of the 1 1/2" drop center area is very generic, not like original bases. As with nearly all TPP reproductions, buyer beware for higher end restoration use.