Manufacturers instructions should always supercede local codes.
IRC - G2422.1.2 (411.1.2) Appliance fuel connectors…shall not be concealed within, or extended through, walls, floors, partitions, ceilings or household appliances…
Exception: fireplace inserts factory equipped with grommets, sleeves or other means of protection in accordance with the listing of the appliance. 
CSST would be the proper fix IMO. There was no shutoff prior to the connector and I’m not aware of the need for one. The code that sticks in my mind requires a shut-off in the same room and within 6 feet of the appliance.
so a black iron pipe through the floor, and then a gas connector would make it ok? sounds like your statement doesnt allow any connections…
The usual method is copper tubing or CSST run through the floor.
(a) All pipe used for the installation, extension,
alteration, and/or repair of any gas piping shall be
standard weight wrought iron or steel, yellow brass
(containing not more than 75% copper), or internally
tinned or equivalently treated copper of iron pipe size.
from the uniform plumbing code… not sure if copper tubing is sufficient material
Copper pipe, or tubing is NEVER ALLOWED BY CODE IN THE US FOR NATURAL GAS DISTRIBUTION! There are various reasons for this which I’m not going to even bother getting into because they are irrelevant. Bottom line is copper is NEVER ALLOWED BY CODE IN THE US FOR NATURAL GAS DISTRIBUTION!
It is very common to see copper tubing used in rural areas for propane gas distribution. This is allowed. Propane and natural gas are two different gasses.
from finishing.com
Actually the chemical additive that corrodes copper is not used anymore.(been debated here many times).
thanks Bob
what exactly do you define as a “connector” any flex hose?
