Klipsch Heresy Speakers Circa 1976 ...Type HDBR

No! If they sound good to you leave them alone! I have a pair just like yours (raw birch) - and they sound just fine! I bought mine for use with my SET 45 and 2A3 amps. With 100db sensitivity the Heresy is a good match for low power amps.

Should you need to rebuilt or want to upgrade you should check out Crites.... they have all sorts of upgrades for Klipsch speakers.....   I love my Heresys.... rock on....

I have a pair of 76 JBL Century's I bought new and they sound better than the day I bought them.  And they have been driven hard.  The first 30 years by a Pioneer SA-9900.  

I also have a vintage pair of heresies that I love, they sounded good when I found them but I rebuilt the crossovers just to see what it would do.  The process is very easy, the crossover could not be easier to access and work on and in my opinion is a very worthwhile upgrade.  I love horns, but they can cause headaches if not done properly... getting everything back to spec seems to have made a huge difference in this regard.  What matters most is what makes you happy, but for 20 minutes of work (and a small investment) you can take them to where they were intended to go.  Add a sub, and congratulations.

I asked my self the same question long time ago (about 17 years ago) when I read somewhere that the crossover of my 1891 HBR is only good for 20 years or so. The majority response I got was “trust your ears.”  If it sounds good to you, leave it alone.  I did. 
Either I got lucky on the crossover or I’m deaf.