IIRC the driver's side antenna was for manual telescoping antennas, & pass. side for power antennas per the 914's radio install'n dealer service bulletin of the day (1970's) &/or 914 factory service manual.
They mostly were delivered without radios, although they could be factory ordered with either a radio & speakers/antenna, or in "radio ready" format, although most were dealer or owner/stereo shop installed.
Click to view attachmentDealer installed had a wider variety of radios (AM, FM & AM/FM), as well as with radio + cassette or 8-Track tape decks, many being offered under the VoA's (Volkswagen of America) VPC label (Volkswagen [USA] Products Corp. - which also sold the dealer installed VPC A/C systems), with the radios & decks mfgd. for VPC by Motorola & others with VW#### model numbers on their chassis (of the radio), as you'll see at the accessories link below.
However, ALL door panel mounted speakers were DAPO add-ons!
Good info. on options & accessories here:
http://bowlsby.net/914/Classic/OpEq.htmhttp://bowlsby.net/914/Classic/Accessories.htmGeneral 914 at 914 info button at the top of page here & at the Originality & History Forum area, as well as:
http://bowlsby.net/914/Classic/http://www.bowlsby.net/914/CanAm/p914.com
PS - the radios & decks sold for the 914s would include knobs to match the lights & other dash switches & a hard plastic cover plate with the 1/2-circle cut-out for the glovebox lock & molded to match the basketweave (70-74 MYs) or brickweave (75-76 MYs) of the vinyl leatherette dash face material's pattern on the rest of the dash. If you get a vintage radio not for the 914, then you'll have to source the proper knobs & faceplate/surround from another old radio or NOS (if that's important to you). They also sold the radio install kits at dealers with the antenna, 2 oval stereo speakers which fit into the plastic speaker housings at the far L & R footwells, & all needed wiring & coax. or other antenna cable.
There are also vendors of retro look modern radios out there online & evil-bay if you want modern sounds/technology or a 3.5 mm & iPad/Phone adapter for your vintage radio (Woody's Customs in Costa Mesa CA for one will be at the Porsche Swap Meet in Anaheim at the Phoenix Club this coming Sunday & also sells on evil-bay).
http://www.bench-racing.com/html/about_us.htmlhttp://motors.shop.ebay.com/woodyscustomshop/m.html