I'd like to try to explore this lock-and-keys situation a bit to get it straight in my mind, if nothing else. Please correct me if I stray.
When longhorn1 says he locks the rear door using the deadbolt, context suggests he's talking about the separate deadbolt, not the deadbolt integrated into the 'black lock'. (I mention this because my Hawk doesn't have a separate deadbolt so I thought he was using the deadbolt on the black lock). The 'black lock' generally supplied by FWC is (I believe) one manufactured by Fastec Industrial Corporation (thus the 'FIC' we read about on the top of some keys). Those lock assemblies were (and are) also available in a chrome finish and with or without the integrated deadlock. The lock assemblies on older FWC units may not have an integrated deadbolt (mine didn't).
Lock assemblies manufactured by Fastec come with keys with black tops and a key-code stamped into the key. The key-code ranges are CF301-CF350, EF301-EF350, HF301-HF350, and CW401-CW434. The key-code is also on a sticker under the backplate of the lock. I don't know what years to associate with the key codes other than to observe that my 2001 Hawk had an assembly with a CF series key code and I know from the Fastec web site that the CW series started in mid-2014.
The black keytops are rectangular for the CF, EF, and HF series and some of them (I don't know which) have FIC embossed on them. The key tops are semi-circular for the CW series and do not have the FIC on them.
Generally, a lock assembly which has two cylinders (latch and integrated deadbolt), will have the same keycode in both cylinders (and therefore one key operates either).
If you have a blue or perhaps a red topped key, it may be cylinder-change key. Some members may have them as leftovers from a lock-cylinder recall started a few years ago for certain HF-series key codes (see Recall info
here). The other possibility is a blank with a blue or red (or other color) top was used to locally create a replacement or spare key.
I recently replaced my 2001-era lock assembly with CF-series cylinders with a new one using CW-series cylinders. I notice the new assembly has dots to indicate cylinder position. The dots are particularly helpful on the integrated deadbolt because it operates a bit oddly. To lock the integrated deadbolt, you turn the key counter-clockwise a half-turn, but then have to turn back a quarter turn to extract the key. The key will not come out of the cylinder at the half-turn position and it doesn't seem logical that the key won't come out. With the dots, I know I need to have the dot to the side for the key to come out after locking.
The separate deadbolt is not a Fastec product. Smoke says his is a 'philips' which I assume means it's a Philips Mobile Home Deadbolt lock
like this one (or similar, perhaps with different finish). Or maybe some have something like this
Kwikset version (or some other). I've noticed some members have had their separate deadbolts re-keyed to match their house keys.
As Paul T mentions, I also notice that my Fastec cylinders need lubrication to operate well. Even my new ones didn't seem to operate well until I lubed them. And even after lubing the key insertion is sometimes not quite as smooth as you would expect.
-Old Crow