.... YAY!!! That's excellent news for you! I feel your joy!
I only hope you enjoy shooting with it as much as I do and look forward to reading your initial thoughts and also subsequent findings.
Of added interest is you shooting with the OM-1 mounted because that's exactly what I shall be doing. In my case I am booked on a flight on March 16th to Portugal to spend 13 full days doing nothing but photography and I really would like to take my pre-ordered OM-1.
With regards to the first wave of OM-1 supplies I am led to believe that it is not unrealistic to expect to receive mine next week as I am as high as #5 in the queue. But of course nothing is absolutely guaranteed yet. The HLD-10 Battery Grips and Dual Battery Chargers may come later but soon after, I am told.
Monday is OM D-Day!! when everyone should have a more accurate picture.
I sold my ED 100-400mm the very first day I advertised it on the E-Group forum but they were in very short supply at that time. I kept the ED 300mm F/4 Pro until very recently and never used it since having my ED 150-400mm TC Pro.