Actually yes, but I had to check the database to see how a normal google map mark was being saved, because the google map mark is an array with the address, the latitude and the longitude, so I had to create the array and then send it to the custom field with update_post_meta
$coordinates = getCoordinates($fullAddress);
$coordinates = explode(",", $coordinates);
$latitude = $coordinates[0];
$longitude = $coordinates[1];
$google_map_mark = array();
array_push($google_map_mark, "address");
array_push($google_map_mark, $fullAddress);
array_push($google_map_mark, "lat");
array_push($google_map_mark, $latitude);
array_push($google_map_mark, "lng");
array_push($google_map_mark, $longitude);
$value = array("address" => $fullAddress, "lat" => $latitude, "lng" => $longitude);
update_post_meta($post_id, 'coordinates', $value);