This is a question will 343 brewing back Recon for halo 3 ?
Nope, sorry OP. Recon was last given out back in 2013 or 2014 and 343 no longer have the tech to grant it to players. If you didn’t earn receive it from Bungie, earn it via Road to Recon or have it granted by 343 then you can no longer get it now.
It is, however, available in MCC to use.