According to my database:
95.5% match to Helvetica Extra Compressed (Adobe Version)
95.1% match to Swiss 911 Extra Compressed (Bitstream)
94.7% match to Helvetica Extra Compressed (Linotype Version)
All of which means that any of these fonts should work. Small variations in percentage get discounted. For example, the Adobe and Linotype versions are known to be identical because Adobe licenses their version from Linotype.