Even with having played Lake Merced at least 700 times, seeing this photo (which I've seen before) and trying to figure out the exact location of the green is really difficult, even with the aerial of the old routing in front of me.
The tee was, as Neil says, near the current 4th tee but it's obvious lots of dirt was moved during the 1964 renovation to build the current 5th hole because the approach shot would be to the left of that green (where that large hill resides in the old photo).
There were only 4 holes on the original layout affected by I-280: #1 (completely lost), #2 (about 1/3 of the fairway), #10 (tee box only), and #9 (the current clubhouse and parking lot eliminated it). The new #4 and #5 were built on property owned by the club adjacent to olde #17 and #18, it would not have been difficult to build those two new holes, slightly shorten #10 (it was a 505 yard par 5, instead it would have been about 480), and just convert #2 (which is where the current #10 is) to a par 3, making it a par 71 but keeping the MacKenzie course virtually intact. I've had almost this exact conversation with Bo Links, who is probably the most knoweldgeable current member, and he was in complete agreement with me.
Add to that all the fill that was brought into the golf course from the highway construction and ruined the sandy nature of the soil permanently and this is clearly a case of a classic golf course turned into something much less although Lake Merced is still a really good, tough golf course. Just not the artistic treasure of the past-what a pity.