Yes the Note 3 has this - not sure if it's part of the S800 based SoC or an extra.
It's a separate chip. These are the latest Qualcomm chips that could turn up in the N5.
Audio codec: WCD9320. It's a big upgrade from the older WCD9310 chip, the N5 is almost guaranteed to have it.
Power management: PM8841/PM8941. These bring Quick Charge 2.0, expect 1.5-2 hour charge times for the 2300mAh model.
Modem baseband: This is now integrated in the S800 SoC. S4Pro/S600 phones needed a separate chip like the MDM9215, so the N5 will have the latest 28nm HPM modem
RF Transceiver: WTR1605L or WTR1625L.
The WTR1605L is found in both Nexus 4 and Note 3 but it's possible another company has been used. The WTR1625L only brings extra GPS functionality which the S800 already has? Could explain why Samsung opted for the older part in the Note 3.
Antenna tuner, amplifier/switch, filter, envelope tracking: QFE15xx, QFE23xx, QFE27xx, QFE11xx.
OEMs usually don't use complete Qualcomm solutions, the Note 3 only has the QFE1100 chip combined with amplifiers, switches etc from Avago/RF Micro etc. The N5 certainly won't have envelope tracking if it's based on the G2, Avago chips were used exclusively in the N4.
Edit: Oh yeah, apparently it's getting a November 14th release date in Japan.
http://www.gsmarena.com/nexus_5_release_date_and_price_leaked_out_of_japan-news-6935.php