Mundgyver, the 9004 & 9007 bulbs accept the same female socket at their bases. If you are making up your own harness the same female socket fits both bulbs.
The bulbs are not interchangeable within the lamp due to different molded "keyways" on the bulbs.
The standard 9007 is 65/55 watts vs. the 65/45 for the standard 9004. The 9007 is in the outboard position of the sport lamps and is the only bulb lit during low beam operation (stock configuration). Perhaps the higher wattage on low beam is the reason D/C uses 9007's?
Even though the same female socket fits the two different bulbs, I believe the three contacts on the 9004 are configured differently than those on the 9007, something to be aware of when making a harness.
One of the items I've seen discussed regarding the non-sport to sport conversion and the decision to light all four low beam filaments at once (instead of the two that D/C lights) has to do with the reflector design. I suspect the main reason only the outboard low beam filaments are enabled by D/C has to do with ease of aiming. The aiming process involves low beams only and two screws that move the entire lamp. It seems to me that enabling all four low beam filaments could slightly complicate the aiming process.
Gifford: I think your 1997 Ram will require mild sheet metal surgery to accept the sport lamps. My 2000 will accept the lamps directly, only requiring wiring changes.
As a side note, the factory service manual indicates that the lamps be removed and reinstalled to replace a defective bulb. The physical install of the sport lamps in model year 2000 and newer can't be too difficu8lt!