No, it will not.
A 3.5 case is too small for a 2.8 and trying to stuff the bigger camera into the smaller case will surely damage the fragile leather. So we are on fairly dangerous ground here.
Over the years I bought and sold a fair few Rollei TLRs, several of which came to me with the wrong cases - a few 2.8s had been wedged into a 3.5 case and it took a careful effort to remove them without damaging the old and often dry leather on those old cases.
One seller of an Automat included a case for a wide angle Rollei. Another 2.8 came with two cases - one for a 3.5 and the other for a Tele-Rollei. The owner had bought the cases separately but had no idea if they would fit or not. At least the 2.8 did fit into the Tele-Rollei case, with a bit of room to spare for accessories...
The plus was I held on to all those ill-fitted cases for about 20 years and later sold them at a good profit when prices for Rollei everything shot up into the upper stratosphere about a decade ago. So yes, the wheel of karma sometimes works in one's favor...