Yes
At least that is the implication in the text.
As they walked through the quiet streets, Vin reached tentatively inside. She eyed Kelsier, then carefully burned that unknown metal. Again, the lines sprang up around her, pointing in seemingly random directions.
The lines moved with her. One end of each thread stayed stuck to her chest, while the other end remained attached to a given place along the street. New lines appeared as she walked, and old ones faded, disappearing behind. The lines came in various widths, and some of them were brighter than others.
The Final Empire - Chapter 7
Additionally, there are many references to Allomancers Pushing/Pulling on something behind them for support. Not to mention that pushing to jump requires the metal to be at least beneath them, if not behind them. So clearly, they are able to sense metal that is not within their direct line of sight.
Vin burned steel, Pushing herself into the cold, humid autumn night. Tin enhanced her eyes, making the wet air tickle her throat as she breathed. She Pushed hard behind her
The Final Empire - Chapter 13
Once she landed on the damp stone, she reached behind and Pulled the bar up into her hand.
The Final Empire - Chapter 13
He’s so strong! Vin thought with horror. [The Inquisitor] was probably steadying himself by Pulling against the lantern brackets behind.
The Final Empire - Chapter 14
Kelsier flared iron — stabilizing himself by Pulling against a lantern bracket behind — then grabbed the iron studs on Demoux’s vest.
The Final Empire - Chapter 21
Vin flared steel, Pushing herself up a bit higher, then flung another coin into the mists behind her. When it hit the wall, she used it to shoot herself forward.
The Final Empire - Chapter 23
Good enough, Vin thought. With a flare of steel, she threw herself into the air, Pushing against a massive iron door behind her.
The Final Empire - Chapter 30
Kelsier Pulled the bars behind him and Pushed the ones in front of him, sending a stream of metal shooting toward the Inquisitor.
The Final Empire - Chapter 34
(emphasis mine)