Originally no, however Directv recently sent out an update to the R15 that enabled a 30 second slip, I am not sure if this update has reached all receivers yet. In a nutshell the answer is yes, very soon all R15's will have the 30 second slip.
If your R15 has already gotten the update from Directv then just press the button above the fast forward button (see picture)...if it has not gotten the update then the 30 slip will not work yet, you can wait a few weeks to get the new update or you can force it by using the 02468 method (if you are not familiar with this method I will post a link explaining it) however this will not guarantee you will get the update.
I have the R15-500, live on the west coast, tried the forced update command, and nothing. It apears the forced update command does not work. When entering the command, there is no alteration in the reset sequence, as if the command was never entered.
I also checked on DBSTalk, there are other people who are experiencing the same issue of not being able to force update, as if the command does not exist. I have also noticed when entering the 02468, while on the first blue Welcome screen, the blue LED does not flash as I key in the code. Durring normal operation, the blue power LED always flashes everytime I press a button on the remote.
Occurs: Daily, at 1:16 AM PT, according to this schedule: Apr 26, 2006 - Pacific time zone R15-500 May 3, 2006 - All time zones R15-300, and all remaining R15-500 receivers Occurs every 20 mins. See To get upgrade. Version after upgrade: 1088 Confirming version: At top of remote, slide to DIRECTV position. MENU on remote. Setup. Info & Test. "System Info" displays the software version. New version of R15-500 is 1088. New version of R15-300 is TBD. What upgrade 1088 does: 30-second "scan": To fast-forward 30 secs, press ADVANCE button (clockwise arrow). To fast-forward in 30-sec blocks, press ADVANCE multiple times. Back-end changes (not readily observable to customer): Improves stability and Series Link support. Previous version: 103A or 10AF In March 2006, an upgrade fixed a problem with recording daily shows using Series Link.:
To get upgrade: Keep receiver plugged in. Does not need to be turned on. If upgrade does not complete: Reset. If receiver just reset, upgrade should occur within 20 minutes.
I have the R15-300 as well and I've received the upgrade