Check out the article at the below address.
Its not exactly half lifes but still an interesting read

http://jpet.aspetjournals.org/content/281/1/93.full.pdf

"Thus, the bioavailability and physiological effects of a nan- drolone ester in an oil vehicle are greatest when the ester is injected in a small (1 ml vs. 4 ml) volume and into the gluteal vs. deltoid muscle. We conclude that the side-chain ester and the injection site and volume influence the pharmacokinetics and pharmacodynamics of nandrolone esters in an oil vehicle in men."

i read a medical study a while back were this was tested.
the conclusion they came to is that the injection site does affect the half life and rate of absorption.

so it definitely has some truth.
but not to the point that you double the half life for one site vs another.

don't remember much about it apart from that injections into larger muscles likes glutes gave much more stable blood levels.

if i can find a link to the study i'll post it here.

whats the science behind that?