On the flame war front: sorry, but you started it, not ghurd (this time ;-).
On topic:
You want a one-word answer to your question, but I can't do it, except to say "no", but it's not just no, it's partly yes, but...
The absorption phase is voltage regulation while the current decreases, then, ideally after the current decreases to a percentage of the battery size (but usually after a fixed time period since cheap charge controllers don't allow you to input your battery size), it decreases to float voltage. This is the "ideal" 3-stage charging.
However, cheaper charge controllers (included those on car alternators) only have two-stages, bulk and absorption/float, i.e., it never reduces the voltage to float. They compromise by having a higher voltage than normal float, but lower than normal absorption. This has the consequence of not fully charging the battery very well; however, it's not too bad in a car because usually the battery is not discharged much.
Also, in a SLA battery instead of a FLA one, the absorption stage is set a bit lower (the 14.1V of a MorningStar SunGuard or equivalent is for a FLA; it's a higher float than I would want for a SLA), and if there is an equalization stage (usually not), it's at a much lower voltage.
The only way you're going to get a charge controller that does proper 3-stage charging for a SLA (there are jumper settings for different battery types) is to pay for it. The cheapest I know of are the MorningStar SunSaver series, about $60 US or so for 10A.
Well, you can also buy yourself a cheap microcontroller (e.g., ATmega48V for $1.90 from futurlec), a Power MOSFET, a gate driver (not really necessary if you set the PWM slow at 3-5kHz, but you'll be able to hear it then) and a few other bits and you can make your own 20A/12/24/48V for about $10 that will do whatever charge algorithm you're willing to code. A great learning experience for someone in college (or even for us older farts ;-).
Dave