Those are later full tapered metering rods, used in a few later model truck applications, mostly heavy duty truck and motorhomes.
They should measure the diameter of the number stamped on them at the top of the second tapered section, then taper down to .036" on the tips.
Using the APT system they will be fine with any main jet you select as far as leaning things up in the normal driving range.
Assuming everything else in the carb is up to par and correct type of float and setting, correct diameter N/S assembly, etc you should only have to drop one jet number to be where you need to be.
As far as idle fuel, it may require smaller idle tubes and DCR's if you can't control the idle fuel with the mixture screws. Those later truck units also used long transfer slots so a LOT of idle fuel comes in below the throttle plates at idle even with the mixture screws fully seated.
As far as tuning parts needed, measure the used metering rods carefully, many will be worn from cavitation or sliding up and down in the jets (flat sided). The jets will be worn internally as well.
I would start by ordering a set of our .071" main jets and team them up with our 50C metering rods. That will lean the carb up everyplace except at idle and provide very precise control of fuel delivery in the "normal" driving range. Our 50C rods are custom machined and full taper and work as replacements for an "M" series or full taper later rod like you are currently using......Cliff
