Don't lose any sleep if you're without a two way valve there, as long as the boost sense hose is in good condition you are probably ok. For a while, or at least until you can get a replacement valve.
I ran a 300TD for two years without a valve. I plumbed the alda directly to the nipple on the back of the intake manifold. I finally found a cheap valve at a wrecking yard and put it in. Its a safety device true, but in reality how often has the wastegate valve failed on the turbo? I know of one case, the boost sense hose ruptured somehow. Its supposed to be silicone rubber Oh say, that reminds me I have a temporary one in place on my 603 engine, using a section of rubber hose I grabbed to get running. tsk
